Using the somatosensory system as a model system, we plan to inject neuronal tracers bilaterally into rat sensorimotor cortex to test the hypothesis that bilateral corticostriatal and corticopontine overlap is greatest for projections from MI sites representing proximal body parts that are bilaterally coordinated. In cats, we will inject neuronal tracers into motor and somatosensory cortex to test the hypothesis that corticopontine projections from SI and SII enable more integration than corticostriatal projections. In the last half of this project we will record multiple neurons in somatosensory cortex simultaneously with neurons in the neostriatum and the pons. We will test the hypothesis that neostriatal neurons discharge mainly when they receive synchronous inputs from related (ie., interconnected) cortical areas in somatosensory cortex. We will also test the hypothesis that stimulus-induced neuronal responses somatosensory are more strongly correlated with responses in the pons than in the neostriatum. PUBLIC HEALTH RELEVANCE: Substantial evidence indicates that the basal ganglia and pontocerebellar systems are responsible for sensorimotor integration and related cognitive processes. By using anatomical tracing methods in combination with sensory stimulation, we will elucidate the circuit mechanisms that mediate sensory processing and will gain valuable insights about the operation of these circuits for processing cognitive information. The potential clinical importance of this work is underscored by the fact that the neural circuits in the basal ganglia and pontocerebellar systems have been implicated in several neurologic disorders including Parkinson's disease, Huntington's chorea, Tourette's syndrome, and other sensorimotor problems.